Cystic fibrosis is the most frequent lethal genetic disease in America. The basic genetic error is unknown. We have previously shown that patients with cystic fibrosis have an inherited defect in beta-adrenergic response which probably resides in the beta receptor or its coupling to adenylate cyclase. This application outlines a systematic investigation of possible biochemical causes for this defect. In samples from cystic fibrosis patients and appropriate control subjects, we will: estimate number and properties of beta adrenergic receptors in lymphocyte and granulocyte membranes by the radioligand binding technique; evaluated phospholipid methylation, which regulates the beta receptor-adenylate cyclase system, in lyphocyte membranes; and investigate the guanine-nucleotide-binding regulatory protein in erythrocytes and lumphocytes. Because patients with cystic fibrosis have inherited increased sensitivity to cholinergic and alpha adrenergic stimuli in vivo, we will investigate these systems in vitro. Cholinergic response will be measured by the stimulation of granylocyte lysosomal enzyme release by carbachol; alpha(2) adrenergic responses will be measured by inhibition of platelet adenylate cyclase activity by norepinephrine. The interactions of alpha, beta, and cholinergic systems will be investigated in the lymphocyte with respect to cAMP formation, phospholipid methylation, and numbers and properties of these receptors on lymphocytes. These studies might identify a membrane-based defect in cystic fibrosis, and will improve our understanding of regulation of beta adrenergic systems in man. In order to determine the possible in vivo significance of these in vitro alpha, beta, and cholinergic measures, we will correlate them with in vivo measures: alpha adrenergic and cholinergic responses will be estimated by the mydriatic and miotic responses to phenylephrine and carbachol and beta responses, by pulse pressure response to isoproterenol. These measures of in vivo autonomic responses will be correlated with in vitro leukocyte alpha, beta, and cholinergic responses in the same subject. These studies may validate the use of leukocytes and platelets as model systems for in vivo autonomic responses.